An experimental study on the effect of magnetic field orientations and electrolyte concentrations on ECDM milling performance of glass

In this work, effects of magnetic field orientation, machining voltage and electrolyte concentration on electrochemical discharge machining (ECDM) performance have been studied. The microchannels have been machined on the glass substrate; microchannel's depth and surface quality have been taken as indexes of machining characteristic. Experimental results show that the Lorenz force of magnetic field affects a direction of bubble's motion, consequently, changes the electrochemical discharge behavior of electrolyte. The presence of magnetic field causes magnetohydrodynamic (MHD) convection which, by its turn, accelerates the repulsion of the bubbles from the cathodic surface. However, it should mention that the direction of bubble movement depends on the magnetic field orientation. If the magnetic field orientation induces upward Lorenz force (downward Lorenz force), the gas bubbles will repel from (will attract to) inter-electrode area. The obtained results demonstrate that when the magnetic field applies, the machined surface will be smoother for the lower concentration values of electrolyte and higher machining voltages. Enhancements of both the machining voltage and electrolyte concentration increase the machining depth. For the same values of applied voltages, application of magnetic field will also increase the machining depth in a certain machining process duration; this will be intensified for the lower values of electrolyte concentration. The results of this study explain how the combination of the magnetic field orientation and the values of machining voltage and electrolyte concentration should be defined in order to increase both the channel depth and surface quality.